The objectives of this project are to study the origins, migrations, interactions and derivatives of neural crest and other primordia involved in normal embryological facial development and to use the information for the study of facial malformations. Other aspects of facial development such as primary palate development are also being studied. The normal aspects of the study are conducted primarily on avian and rodent embryos. Extensive use is made of cell, tissue and organ culture procedures. Various histological and biochemical techniques are used. These include radioautography (and other procedures for following the migrations of cells) histochemistry, and column chromatography, as well as interference contrast and electron microscopy. The embryogenesis of spontaneous and induced malformations, particularly cleft lip and palate, is being studied in the mouse. Efforts are being made to influence the abnormal processes leading to "spontaneous" clefts through manipulation of environmental factors.